<PRE><B>Question 879679</B>
The idea is to factor 2205 into two numbers where one is a perfect square. Then we use the rule {{{sqrt(x*y)=sqrt(x)*sqrt(y)}}}



{{{sqrt(2205) = sqrt(441*5)}}} Notice how 441 is a perfect square (441 = 21^2)


{{{sqrt(2205) = sqrt(441)*sqrt(5)}}}


{{{sqrt(2205) = sqrt(21^2)*sqrt(5)}}}


{{{sqrt(2205) = 21*sqrt(5)}}}</PRE>